With the rapid development of stereoscopic display technology, one of the current mainstream naked eye three dimension (3D) display technology is stereoscopic display technology based on parallax, which mainly includes two types: a grating type and a lens array type. With the development of liquid crystal technology, liquid crystal materials are widely used in various fields. A liquid crystal grating is an active grating, which can not only achieve three-dimensional stereoscopic display, but also can switch between three-dimension display and two-dimension (2D) display.
The principle of 3D display using a liquid crystal grating LR will be firstly introduced below with reference to FIG. 1. The liquid crystal grating LR with light transmissive areas distributed at intervals is placed in front of a display panel DP, the liquid crystal grating LR is a “parallax barrier”, and an image displayed by the display panel DP includes two signals, namely left eye image information (L) and right eye image information (R).
In a 3D display mode, the left eye image information and the right eye image information of the display panel DP are separated by the liquid crystal grating LR, such that the left eye of a user can only receive the left eye image information while the right eye can only receive the right eye image information, in order to achieve a 3D display effect.
The structure of the liquid crystal grating is as shown in FIG. 2, and sequentially includes the following components from top to bottom: a second polarizing film 21, a second substrate 22, a second electrode structure 23, a second alignment layer 24, a liquid crystal layer 25, a first alignment layer 27, a first electrode structure 26, a first substrate 28 and a first polarizing film 29.
The second substrate 22 and the first substrate 28 are opposite and are arranged in parallel. The second electrode structure 23 is arranged at the inner side of the second substrate 22 (i.e., the side of the second substrate 22 facing to the liquid crystal layer 25), the first electrode structure 26 is arranged at the inner side of the first substrate 28 (i.e., the side of the first substrate 28 facing to the liquid crystal layer 25), the liquid crystal layer 25 is arranged between the second electrode structure 23 and the first electrode structure 26, the second alignment layer 24 is arranged between the liquid crystal layer 25 and the second electrode structure 23, and the first alignment layer 27 is arranged between the liquid crystal layer 25 and the first electrode structure 26. The alignment direction of the second alignment layer 24 is perpendicular to that of the first alignment layer 27, such that liquid crystal molecules 251 in the liquid crystal layer 25 can be aligned.
The second electrode structure 23 is a surface electrode, and the first electrode structure 26 includes a plurality of electrode strips 30 arranged at equal intervals. When the electrode strips 30 of the liquid crystal grating are energized, the liquid crystal molecules 251 corresponding to the electrode strips 30 deflect, while the other liquid crystal molecules 251 do not deflect. At this time, after entering the liquid crystal layer, light will gradually change its polarization direction when passing through the undeflected liquid crystal molecules 251, the vibration direction of polarized light arriving at the first polarizing film 29 is just parallel to the absorption axis of the first polarizing film 29, then the light passes to form the light transmissive area of the liquid crystal grating; when passing through the deflected liquid crystal molecules 251, the light will not change its polarization direction, the vibration direction of the polarized light arriving at the first polarizing film 29 is perpendicular to the absorption axis of the first polarizing film 29, then the light cannot pass and thus a non-light transmissive area of the liquid crystal grating is formed, in this way, the left eye image information and the right eye image information are separated to achieve the 3D display effect.
The driving circuit structure of the existing liquid crystal grating is as shown in FIG. 3 and FIG. 4. FIG. 3 and FIG. 4 respectively represent two different implementation forms of electrode strips 30 and control lines 31, the common ground of the two forms of the driving circuit structures lies in that all the electrode strips 30 of the liquid crystal grating are connected via one control line 31. At a working state, the driving circuit provides the same driving voltage for each electrode strip 30. Although the structure design is easy to drive and control, the width of the light transmissive area or the non-light transmissive area of the liquid crystal grating is difficult to adjust, thus a crosstalk phenomenon is easily occurred.
A liquid crystal grating for solving the crosstalk problem exists in the prior art as well, the schematic diagram of the driving structure thereof is as shown in FIG. 5 and FIG. 6. It is found through comparison between FIGS. 3 and 4 and FIGS. 5 and 6 that, the biggest difference is: there is no longer only one control line 31 in FIG. 5 and FIG. 6, while the electrode strips 30 are connected with the driving circuit of the liquid crystal grating through different control lines 31 to adjust the sizes of the light transmissive areas of the liquid crystal grating, namely, the widths of the light transmissive areas or the non-light transmissive areas of the liquid crystal grating can be controlled by the driving circuit.
Although the liquid crystal grating as shown in FIG. 5 and FIG. 6 can adjust the light transmissive areas of the grating, each electrode strip 30 needs to be provided with one independent control line 31 to be connected with the driving circuit, this not only will increase the difficulty of the manufacturing process, but also will make the driving circuit become more complicated.
To sum up, in the existing liquid crystal grating technology, the driving circuit structure of the liquid crystal grating easy to drive and control cannot adjust the sizes of the light transmissive areas of the grating, while the driving circuit structure of the liquid crystal grating capable of adjusting the sizes of the light transmissive areas of the liquid crystal grating is very complicated.